The fabrication of large structures may involve the performance of a large number of manufacturing operations on the structure, such as the drilling of a large number of holes. Conventional structures that require a large number of manufacturing operations include, for example, aircraft, missiles, ships, railcars, sheet metal buildings, and other similar structures. In particular, conventional aircraft fabrication processes typically involve the drilling of a large number of holes in wing sections of the aircraft to allow these sections to be attached to each other and to the airframe.
A variety of devices have been developed to facilitate drilling operations involving the drilling of a large number of holes. For example, U.S. Pat. No. 4,850,763 issued to Jack et al. discloses a drilling system that includes a pair of rails temporarily attached to an aircraft fuselage. A support carriage is slideably coupled to the rails and supports a drill assembly. A template attached to the aircraft fuselage provides an indication of the desired locations of the holes that are to be formed in the aircraft fuselage. As the carriage is moved along the rails, a locking mechanism (or trigger) interacts with the template to securely position the carriage for a subsequent drilling operation.
Although desirable results have been achieved using the prior art drilling systems, there is room for improvement. For example, prior art assemblies typically need to be carefully oriented on the workpiece prior to performing manufacturing operations to ensure that the manufacturing operations are performed in the proper locations. Orienting the prior art assemblies on the workpiece may require physical contacts between the support carriage or other portions of the assembly and one or more contact points on the workpiece. Such physical contacts may be subject to degradation, especially through repeated usage, and may also adversely impact the quality of some types of workpiece surfaces. Therefore, a need exists for an improved position orientation system for performing manufacturing operations on a workpiece.
Furthermore, prior art manufacturing assemblies typically include a controller that is positioned remotely from the support carriage that supports a tool assembly over the workpiece, as disclosed, for example, in U.S. Pat. No. 6,550,129 B1 issued to Buttrick and U.S. Pat. No. 6,073,326 issued to Banks et al. In such systems, control signals for commanding movement of the support carriage and for controlling manufacturing operations using the tool assembly are transmitted via a system of control cables that extend between the remotely-positioned controller and the components of the support carriage and the tool assembly. Although desirable results have been achieved using such manufacturing assemblies, the extent of movement of the support carriage and the operation of the tool assembly may be limited by the lengths of the control cables or by the mobility of the controller within the confines of the manufacturing environment.